Most everyone is familiar with the disastrous consequences of the war on drugs: drug gangs, drug lords, drug suppliers, gang wars, muggings, robberies, thefts, corruption of judges, prosecutors, and law-enforcement officials, murders, assassinations, overcrowded jails, asset forfeiture, and on and on. The fact is that nothing good is produced by the war on drugs. All the results are bad. If you have any doubts, just ask the people of Mexico, who have experienced the unbelievable number of 30,000 drug war deaths in the last 3 years alone.
Making drugs illegal causes the price to increase, which motivates suppliers to enter the black market to make money. The state gets angry over this economic phenomenon, imposing harsher penalties and more brutally enforcing the laws. That causes prices to go up even more, which motivates more people to enter into the market as suppliers. Ultimately, the black market price gets so high that ordinary citizens are lured into the market in the hopes of scoring big financially.